Field of the Invention
The present invention relates to a sheet discharge device which discharges a sheet, and an image forming apparatus having the sheet discharge device.
Description of the Related Art
A conventional sheet discharge device discharges a sheet such as a transferred sheet on which an image is formed from a main body of the image forming apparatus. The sheet discharge device includes a driving roller which receives a sheet on which an image is fixed by a fixing device to convey or discharge the sheet, and a driven roller which is driven and rotated by being pressed against the driving roller.
When discharging the sheet from the main body of the image forming apparatus onto a discharge tray, the sheet discharge device rounds or skews on the sheet discharge tray due to thermal deformation after fixing, which causes problems in terms of stacking properties. For this reason, the sheet is slightly curved in a width direction orthogonal to a conveying direction (discharge direction) by stiffening rollers to perform stiffening and ensure the stacking properties.
Specifically, as a conventional sheet discharge device, a configuration has been proposed in which a stiffening roller having a diameter larger than that of the driving roller is provided on the roller shaft of the driving roller, and the sheet is slightly curved in the width direction orthogonal to the conveying direction by the stiffening roller and is discharged in the state of being stiffened (Japanese Patent Laid-Open No. H2-305771).
However, in the conventional sheet discharge device, when a thick sheet is conveyed, an entry angle of the sheet to the stiffening rollers having a larger diameter than that of the driving roller becomes worse than the entry angle of the sheet to the driving roller, there is a problem which causes folding or jamming of edge of the sheet (end of the sheet).
Therefore, it is desirable to prevent folding or jamming of the edge of the sheet (end of the sheet) due to the leading end of the sheet abutting on the surface of the stiffening roller.